While in the prior art, various burglar alarm devices have been proposed for preventing the theft of gasoline from the fuel tank of an automotive vehicle, such devices required an additional switch to be installed proximate the gasoline cap such as for detecting the removal of the cap or the movement of a cover thereover. Illustrative are U.S. Pat. Nos. 3,873,966 and 3,878,507.
Float controlled potentiometers are utilized in the fuel tanks of most automotive vehicles to form a gas guage in conjunction with a dashboard mounted meter movement. The resistance of the float potentiometer increases with increasing fuel level in vehicles made by some manufacturers and decreases with increasing fuel level in vehicles made by other manufacturers.